Microsoft is inviting New York and San Francisco press and analysts to an October 3 event involving Hotmail. Here's the invitation:

"We listened. We learned. We reinvented Hotmail from the ground up," says the invitation. "From performance to spam to security and more, we're going to challenge your perceptions and show how we stack up against the competition."

There's no indication beyond those words as to what this press event will be about. But I have a theory, based on tips I received earlier this year. I'm thinking this could be the rollout of an HTML5 version of Hotmail -- one that would offer offline access.

Microsoft's not sharing anything beyond what's in this email. But the timing would make sense, given the Softies are ready to start rolling out test builds of Windows 8 optimized for tablets. In the past few days, both Samsung and ASUS have been talking up their new Windows 7 tablets that hopefully will be Windows 8 compatible and upgradable. And Microsoft is expected to provide Build attendees with a tablet of some sort (I still hear Intel-based) running the Windows 8 bits.

Microsoft is known to be readying an HTML5 version of Bing that looks a whole lot like the Bing iPad application. (I'm not clear right now if this is a Web site/app or a "native" application... or both.) Another app that could really show off what HTML5 apps can do would be Hotmail... especially if coupled with an updated SkyDrive cloud-storage service (with maybe even more storage than the 25GB currently offered).

Regardless of outcry or lack thereof, the outage was a black eye for Microsoft's cloud offerings. That said, I've had a Hotmail account for a couple of years now and have to say I've been pleasantly surprised with the relative lack of spam and increasingly frequent introduction of new features.

Anyone have any other guesses (educated or not) about what Hotmail press event next month will address?

Update: Microsoft officials are pouring cold water on my theory and are saying a bit more as of this evening. A spokesperson said: "This event is not considered a launch of a reinvented Hotmail. The event will include an intimate, honest discussion and new data linked to the reinvention that took place last year (plus updates since then), based on a lot of learning. You'll also hear about intriguing competitive perspectives and some additional news."

I'll be surprised if Microsoft holds a big press event with nothing but a little "additional news." I guess we'll have to wait until Oct. 3 for more (unless anyone shares more specifics on what might be happening before that).